Lox Showcase

[emilkrebs]

Two steps are needed first in order to publish this

1. Modified the language server so it sends the results of the interpreter TypeFox/langium-lox#3 is needed first and has to be published on npm
2. Add the package to the dependencies

[Lotes]

Having unknown type is not so nice. There is a easy pattern I use:

type XType = 'A'|'B'|'C';
interface XBase {
  type: XType;
}

interface A extends XBase {
  type: 'A'; // subset of parent definition!
  content: string;
}

interface B extends XBase {
  type: 'B'; // subset of parent...
  content: number;
}

interface C extends XBase {
  type: 'C';
  content: boolean;
}
type X = A|B|C;

//usage: you can do stuff like this:
const x: X = ... //get from somewhere
if(x.type === 'A') {
   //it asserts then that x is of type A, so accessing x.content will be a string, no casts needed!!!
} else if(x.type === 'B') {
  //...x.content is number
} else if(x.type === 'C') {
  //...x.content is boolean
} else {
  assertUnreachable(x.type); //this code is then unreachable (it will be highlighted red when another type D was added)
}

[emilkrebs]

The interpreter returns an unknown type, so I could do something like this:

export interface LoxMessage {
    type: LoxMessageType;
    content: MessageContent;
};

type MessageContent = string | number | boolean | null | any;

[Lotes]

Use the same trick as above to avoid Union type for content

[spoenemann]

@emilkrebs please squash your commits and rebase to the latest changes on the main branch: we've now switched deployment to GH Pages.